I have this problem, but it is on btwdins.exe. I also used Process Explorer to find out about the DLL, and it generally uses about 20% CPU (out of the computer below - core 2 duo 2ghz). Lately I have just been suspending it whenever I see hard drive and CPU activity ramp up really high (suspending the DLL thread, not the whole process) but I don't get it - my bluetooth device is off, so why would it be using so much CPU?
I did a 2-second log of the process with Regmon (another Sysinternals tool) and it made 7,690 registry queries!!
A 2-second Filemon gives similar results - 7499 file queries!
That is an insane amount of activity that should never happen except when doing something like an antivirus scan... In my case, I might be able to solve it by changing out Bluetooth drivers, but for your case, I don't know. The "Security Center" thing sounds like a firewall or antivirus program that you might have installed.
I think I might submit this in some other places, and maybe see if I can get hold of a Microsoft expert to give me a definitive answer. I don't want my laptop hard drive under this kind of stress, and I don't want to go kill the thread every time I start up the computer (or whenever it mysteriously starts up again).
 WOW, I had no idea this thread was sooo old until just now, when I noticed the original post date. Sorry for digging it up from the grave but it's a problem I'm currently having! [/edit]